I would have to say my health teacher in high school. He was the cutest guy that I had ever seen and he was only 24 years old so he was very young. All the girls in the class were crushing on him and you could tell because we were so focused and had our eyes on him the whole class. The funny part was that he knew how much we liked him and so he was always talking about his wife in class. I guess he wanted us to know he was happily married lol.
I had a 24 year old English teacher when I was in 11th grade who was very flirty with me. In college I had several science TAs that were into me. Hung out with one for drinks and sushi. Another turned into a fling and got us both into a little trouble when it crashed. =P
While it wasn't an attraction by any means, I had a crush on my kindergarten teacher when I was only five years old. She was attractive to such a young mind at the time and she was really good with us all.